Sample exam questions - chemical changes - AQAMaths questions

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.

Part ofChemistry (Single Science)Chemical changes

Maths questions

Don't forget to take a ruler and calculator into the exam.

Maths questions often start with the command word calculate. You need to use numbers given in the question to work out the answer.

When an answer to a maths question is marked:

  • full marks are given for the right answer
  • marks may be given for working, including substitution and rearrangement
  • errors carried forward are worked through to give credit for later working

Learn maths skills with Dr Alex Lathbridge

Brush up on the maths you need for your exam - percentages, averages and converting units.

Make sure you give answers to a suitable number of significant figures.

Maths questions might ask you to plot or complete a graph or table. When you draw a graph, make sure you:

  • plot each point accurately
  • draw a best fit straight line or curve, where appropriate

You may be given a grid with axes labelled and scales already given. Sometimes you may be given an empty grid for you to supply your own axes. When you do this:

  • put the independent variable on the x-axis and the dependent variable on the y-axis
  • choose even scales and make sure that the points cover at least half the given grid
  • label the axes with their quantity and unit, eg time (s)

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

Sample question 1 - Foundation

Question

A student wants to find out the volume of hydrochloric acid that reacts with 25.0 cm3 of sodium hydroxide solution.

He carries out a titration. Table 1 shows his results.

Titration 1Titration 2Titration 3Titration 4
Final burette reading37.60 cm336.20 cm339.15 cm338.40 cm3
Initial burette reading1.80 cm30.00 cm33.95 cm32.10 cm3
Volume of acid used35.80 cm336.20 cm335.20 cm336.30 cm3
Final burette reading
Titration 137.60 cm3
Titration 236.20 cm3
Titration 339.15 cm3
Titration 438.40 cm3
Initial burette reading
Titration 11.80 cm3
Titration 20.00 cm3
Titration 33.95 cm3
Titration 42.10 cm3
Volume of acid used
Titration 135.80 cm3
Titration 236.20 cm3
Titration 335.20 cm3
Titration 436.30 cm3

a Which two results are within 0.10 cm3 of each other?

[1 mark]

Titration _____ and titration ______.

b Use your answer to part a to calculate the mean volume of acid required.

[2 marks]

Sample question 2 - Foundation

Question

A student electrolysed copper sulfate solution for five minutes.

Table 1 shows his results.

Table 1

AnodeCathode
Mass of electrode before electrolysis1.16 g1.28 g
Mass of electrode after electrolysis0.85 g1.57 g
Mass of electrode before electrolysis
Anode1.16 g
Cathode1.28 g
Mass of electrode after electrolysis
Anode0.85 g
Cathode1.57 g

Calculate the mass of copper deposited on the cathode.

[2 marks]

Sample question 3 - Higher

Question

25.0 cm3 of 0.1 mol/dm3 sodium hydroxide solution reacts with 26.20 cm3 of sulfuric acid solution.

Calculate the concentration of the sulfuric acid, in mol/dm3.

[4 marks]

Sample question 4 - Higher

Question

A student adds water to a sample of dilute hydrochloric acid.

The concentration of hydrogen ions decreases by a factor of 100.

Predict the effect on the pH.

[2 marks]